Exploiting species-specific behavioural responses of fish to light is an increasingly promising technique to reduce the entrainment or impingement of fish that results from the diversion of water for human activities, such as hydropower or irrigation. Whilst there is some evidence that white light can be an effective deterrent for Chinook salmon smolts, the results have been mixed. There is a need to test the response of fish to different spectra and strobing frequencies to improve deterrent performance. We tested the movement and spatial response of groups of four fish to combinations of light-emitting diode (LED) spectra (red, green, blue and white light) during the day and night, and strobing frequencies (constant and 2Hz) during the day, using innovative LED technology intended as a behavioural guidance device for use in the field. Whilst strobing did not alter fish behaviour when compared to constant light, the red light had a repulsive effect during the day, with fish under this treatment spending significantly less time in the half of the arena closest to the behavioural guidance device compared to both the control and blue light. Importantly, this effect disappeared at night, where there were no differences in movement and space use found between spectra. There was some evidence of a potential attractive response of fish to the blue and green light during the day. Under these light treatments, fish spent the highest amount of time closest to the behavioural guidance device. Further tests manipulating the light intensity in the different spectra are needed to verify the mechanistic determinants of the observed behaviours. Results are discussed in reference to the known spectral sensitivities of the cone and rod photopigments in these fish, and further experiments are suggested to better relate the work to mitigating the effects on fish of infrastructure used for hydropower and irrigation.

Malaria at international borders presents particular challenges with regards to elimination. International borders share common malaria ecologies, yet neighboring countries are often at different stages of the control-to-elimination pathway. Herein, we present a case study on malaria, and its control, at the border between Saudi Arabia and Yemen. Malaria program activity reports, case data, and ancillary information have been assembled from national health information systems, archives, and other related sources. Information was analyzed as a semi-quantitative time series, between 2000 and 2017, to provide a plausibility framework to understand the possible contributions of factors related to control activities, conflict, economic development, migration, and climate. The malaria recession in the Yemeni border regions of Saudi Arabia is a likely consequence of multiple, coincidental factors, including scaled elimination activities, cross-border vector control, periods of low rainfall, and economic development. The temporal alignment of many of these factors suggests that economic development may have changed the receptivity to the extent that it mitigated against surges in vulnerability posed by imported malaria from its endemic neighbor Yemen. In many border areas of the world, malaria is likely to be sustained through a complex congruence of factors, including poverty, conflict, and migration.

The ghost city phenomenon is a serious problem resulting from the rapid urbanization process in China. Estimation of the ghost city rate (GCR) can provide information about vacant dwellings. This paper developed a methodology to quantitatively evaluate GCR values at the national scale using multi-resource remote sensing data. The Suomi National Polar-Orbiting Partnership–Visible Infrared Imaging Radiometer (NPP-VIIRS) night-time light data and moderate resolution imaging spectroradiometer (MODIS) land cover data were used in the evaluation of the GCR values in China. The average ghost city rate (AGCR) was 35.1% in China in 2013. Shanghai had the smallest AGCR of 21.7%, while Jilin has the largest AGCR of 47.27%. There is a significant negative correlation between both the provincial AGCR and the per capita disposable income of urban households (R = −0.659, p < 0.01) and the average selling prices of commercial buildings (R =−0.637, p < 0.01). In total, 31 ghost cities are mainly concentrated in the economically underdeveloped inland provinces. Ghost city areas are mainly located on the edge of urban built-up areas, and the spatial pattern of ghost city areas changed in different regions. This approach combines statistical data with the distribution of vacant urban areas, which is an effective method to capture ghost city information.

Reducing the potential for crashes involving front line service workers and passing vehicles is important for increasing worker safety in work zones and similar locations. Flashing yellow warning beacons are often used to protect, delineate, and provide visual information to drivers within and approaching work zones. A nighttime field study using simulated workers, with and without reflective vests, present outside trucks was conducted to evaluate the effects of different warning beacon intensities and flash frequencies. Interactions between intensity and flash frequency were also analyzed. This study determined that intensitiesof 25/2.5 cd and 150/15 cd (peak/trough intensity) provided the farthest detection distances of the simulated worker. Mean detection distances in response to a flash frequency of 1 Hz were not statistically different from those in response to 4 Hz flashing. Simulated workers wearing reflective vests were seen the farthest distances away from the trucks for all combinations of intensity and flash frequency.

Artificial light at night (ALAN) affects over 20% of the earth's surface and is estimated to increase 6% per year. Most studies of ALAN have focused on a single mechanism or life stage. We tested for indirect and direct ALAN effects that occurred by altering American toads' (Anaxyrus americanus) ecological interactions or by altering toad development and growth, respectively. We conducted an experiment over two life stages using outdoor mesocosms and indoor terraria. In the first phase, the presence of ALAN reduced metamorphic duration and periphyton biomass. The effects of ALAN appeared to be mediated through direct effects on toad development, and we found no evidence for indirect effects of ALAN acting through altered ecological interactions or colonization. In the second phase, post-metamorphic toad growth was reduced by 15% in the ALAN treatment. Juvenile-stage ALAN also affected toad activity: in natural light, toads retreated into leaf litter at night whereas ALAN toads did not change behaviour. Carry-over effects of ALAN were also present; juvenile toads that had been exposed to larval ALAN exhibited marginally increased activity. In this time frame and system, our experiments suggested ALAN's effects act primarily through direct effects, rather than indirect effects, and can persist across life stages.